In certain types of signal, effects arising from certain types of interference burst contained within the signal cannot be removed entirely unless each of the bursts can be substituted by an accurate estimate of the original signal waveform in the corresponding regions of the signal. This may be possible to an acceptable degree of precision when a wanted signal is strong and not corrupted by noise, but in the case where the wanted signal is weak and not visible above the level of the noise or of other unwanted signals, substitution cannot necessarily be performed. It should also be noted that simple excision of the interference bursts is ineffective since this merely has the effect of replacing one interfering signal with another.
It is increasingly common for signal processing to be carried out digitally in the frequency domain, in modems for example. Certain types of regular or quasi-regular interference burst contained in signals, when processed in the frequency domain, can be particularly disruptive. A common source of such interference is ignition noise generated within motor vehicle engines. However, while the effects of such interference are particularly noticeable in frequency domain signal processing, equivalent degradation may also arise in time domain processing of such signals and the principles of the present invention may also be applied to such applications.